This invention relates to an improved electrical method and apparatus for determining the location of a leak in a pipe buried in the ground and is applicable to any type of pipe or tube which is made of an electrically insulating material. Such pipes are widely used, for example, in connection with swimming pool installations, irrigation systems, gas lines, and also conduits for carrying electrical wires for telephone and power purposes. Commonly employed electrically insulating materials for such pipes, tubes, and conduits have been polyethelene and polyvinyl chloride (PVC), but the method and apparatus is usable with pipes, tubes, and conduits of other electrical insulating materials as well.
In the past several methods have been employed when a leak is known to occur in an underground pipe, especially those used for conducting water. One such method is to inject a radioactive material in the fluid, and subsequently wash out the fluid containing the radioactivity. Some radioactivity will remain in the ground in the vicinity of the leak. By the use of a radioactivity detector such as a Geiger counter, the region of radioactivity can often be found, thus localizing the region of the leak. The accuracy of localization is however not high, due to the spread of radioactivity, and the difficulty of finding the point of maximum activity. Further, the method is restricted to pipes which are not buried at large distances from the surface as the radioactivity at the surface will be reduced, and spread in area. Also special health safeguards are required when using radioactive substances.
Another method employed is to force water into the pipe under pressure, and to listen for the sound of the water forced through the leak. This method while useful in detecting the general region of a leak, is not very precise.
The advantages of my improved electrical method are that it gives a precise distance for the location of the leak, employs no substances which could be harmful to health, and is simple to employ.